The present invention relates to the field of devices for packaging and dispensing a liquid or semi-liquid fluid, in particular a cosmetic.
The invention relates more particularly to devices including a manually-actuated pump for dispensing a quantity of fluid.
In conventional manner, such pumps comprise a pushbutton defining a bearing surface for the user that is mounted at the top end of a hollow control rod for the pump and that is to be depressed at the time of use.
It is known to use a metal spring to return the pushbutton to its initial position after dispensing a quantity of fluid.
Nevertheless, the use of such a metal spring increases the cost price of the pump and can give rise to problems of corrosion and compatibility with the fluid dispensed.
U.S. Pat. No. 5,363,993 proposes a pump in which the pushbutton is secured to a spring-forming bellows, enabling it to be returned to its initial position after dispensing a quantity of fluid.
Such a bellows is relatively bulky and unattractive in appearance, and it requires a skirt of trim to be provided around it.
In addition, such a bellows is difficult to mold.
The invention seeks in particular to remedy the above-mentioned drawbacks in full or in part.
The invention achieves this by means of a novel pushbutton for actuating a dispenser member, the dispenser member having a moving element that is movable between two positions, the pushbutton having a base, a head defining both a bearing surface for a user and a dispensing orifice, and an elastically-deformable portion interconnecting the base and the head, the head being suitable for being secured to the moving element, and wherein the elastically-deformable portion is arranged so as to deform in the sense of rolling onto itself when the head is depressed and is suitable for returning the moving element into an initial position by resilient return.
The elastically-deformable portion thus deforms in the present invention in a manner different from that of a bellows or a helical spring, since a bellows or a helical spring does not deform in the sense of rolling onto itself, but in the sense of being compacted in an axial direction.
The pushbutton of the invention makes it possible to avoid using a metal spring for returning the pump to its initial configuration after dispensing a quantity of fluid, and to do so without presenting the above-mentioned drawbacks of U.S. Pat. No. 5,363,993.
The pushbutton of the invention is also easily manufactured by molding a plastics material and it can be made to have a shape that is pleasing in appearance, thus making it possible to omit a skirt of trim surrounding the elastically-deformable portion.
In a particular embodiment, the elastically-deformable portion is generally dome-shaped.
The head is preferably situated in the center of the elastically-deformable portion.
Such a configuration makes it possible to facilitate displacement in translation of the head when the user presses against it.
Advantageously, the elastically-deformable portion is arranged to form a fold when the head is depressed, and from at least a certain down stroke of the head, the zone connecting the head to the elastically-deformable portion passes beneath the level of the top of the fold.
In a particular embodiment, the elastically-deformable portion is of substantially constant thickness.
Still in a particular embodiment, the elastically-deformable portion has no folds when at rest.
Such folds could be unattractive in appearance and could encourage the accumulation of dirt.
In a particular embodiment, the base of the pushbutton is tubular in shape, and is preferably circularly symmetrical.
In a particular embodiment, the head includes an endpiece enabling it to be fixed onto a pump control rod.
The endpiece can extend below the level of the coupling zone between the elastically-deformable portion and the head.
In a particular embodiment, the head includes a housing enabling a nozzle to be secured thereto.
The axis of the nozzle may be perpendicular to the direction in which the head is depressed in order to dispense a quantity of fluid, or in a variant it can have some other orientation.
In a particular embodiment, the elastically-deformable portion is connected to the head substantially perpendicularly to the direction in which the head is depressed in order to dispense a quantity of fluid.
Such a configuration makes it possible to cause the elastically-deformable portion to roll onto itself from the beginning of the depression stroke of the head.
In a particular embodiment, the elastically-deformable portion is connected to the head via a zone of reduced thickness.
Such a zone of reduced thickness facilitates moving the head in translation when it is depressed.
Advantageously, the base is arranged to engage on a pump body, in which case it preferably includes an annular bead in the zone used for fixing to the pump body.
Such a bead makes it possible to obtain a stronger clamping force for holding the pushbutton in place on the pump body.
The thickness of the elastically-deformable portion can lie in the range 1 millimeter (mm) to 3 mm, for example, and is preferably close to 2 mm.
In a particular embodiment, the head of the pushbutton has an enlarged top end.
Preferably, the pushbutton is made as a single piece by molding.
The plastics material used for molding the pushbutton can be a material having shape memory, preferably a material selected from mixtures based on the following materials: ethylene vinyl acetate, thermoplastic elastomers, and low density polyethylene.